Study of X - Ray Spectra and its types

A Brief Review of X-ray production and study of its different spectra i.e. continuous and characteristic spectra with its varied applications.

1. X-Ray Spectra Presented By : Tanisha Shukla MSc-1 Department of Physics Rtmnu,Nagpur

2. Discovery X-rays were discovered in 1895 by Wilhelm Conrad Röntgen, who received the first Nobel Prize in Physics in 1901. Experimental Set-up

3. Location of X-ray in Electromagnetic spectrum

4. X-ray is a high-energy electromagnetic radiation X-rays have a wavelength ranging from : 1. Soft X-Rays: 10 nanometers ,f= 30 petahertz (3×10 ^ 16 Hz ) & Energy= 100 eV 2. Tender X-Rays: 3. Hard X-rays: 10 picometers, f= 30 exahertz ( 3×10 ^ 19 Hz) & Energy= 100 keV X - Rays :

5. A current is passed through the tungsten filament and heats it up. As it is heated up the increased energy enables electrons to be released from the filament through thermionic emission. The electrons are attracted towards the positively charged anode and hit the tungsten target with a maximum energy determined by the tube potential (voltage). The x-ray photons are released in a beam with a range of energies (x-ray spectrum) out of the window of the tube and form the basis for x-ray image formation. Production of X rays

6. A bombarding electron knocks a k-shell or l-shell electron out. A higher shell electron moves into the empty space. This movement to a lower energy state releases energy in the form of an x-ray photon. The bombarding electron continues on its path but is diverted. Characteristic Radiation at Anode:

7. Types of X-Rays: There are two types of X-Rays: 1.Continuous X-Ray 2. Characteristic X-Ray Continuous X-Ray Emission Spectra: When a fast moving electron penetrates and approaches a target nucleus, the interaction between the electron and the nucleus either accelerates or decelerates it which results in a change of path of the electron. The radiation produced from such decelerating electron is called Bremsstrahlung or braking radiation. The energy of the photon emitted is equal to the loss of kinetic energy of the electron. Since an electron may lose part or all of its energy to the photon, the photons are emitted with all possible energies (or frequencies). The continuous x-ray spectrum is due to such radiations. When an electron gives up all its energy, then the photon is emitted with highest frequency (or lowest wavelength λ). The initial kinetic energy of an electron is given by eV, where V is the accelerating voltage .

8. Therefore, we have

9. Characteristic X-Ray emission Spectra: Characteristic X-rays are emitted when outer-shell electrons fill a vacancy in the inner shell of an atom, releasing X-rays in a pattern that is "characteristic" to each elem ent . Characteristic X-rays are produced when an element is bombarded with high-energy particles, which can be photons, electrons or ions (such as proton s). When the incident particle strikes a bound electron (the target electron) in an atom, the target electron is ejected from the inner shell of the atom. After the electron has been ejected, the atom is left with a vacant energy level, also known as a core hole. Outer-shell electrons then fall into the inner shell, emitting quantized photons with an energy level equivalent to the energy difference between the higher and lower states. Each element has a unique set of energy levels, and thus the transition from higher to lower energy levels produces X-rays with frequencies that are characteristic to each element.

10. Sometimes, however, instead of releasing the energy in the form of an X-ray, the energy can be transferred to another electron, which is then ejected from the ato m. This is called the Auger effect , which is used in Auger electron spectroscopy to analyze the elemental composition of surfaces.

11. X-Ray Emission Spectra

12. X ray spectrometry (XRS) techniques are used for the elemental, chemical, crystalline, structural and dynamic analysis of a broad range of materials fulfilling a wide variety of requirements. Determining the atomic structure of a sample. Determining the metabolic structure of a muscle. Monitoring dissolved oxygen content in freshwater and marine ecosystems. Studying spectral emission lines of distant galaxies. Altering the structure of drugs to improve effectiveness. Applications

13. Refrences: 1. X-Ray Spectroscopy by Leonid V. Azaroff 2. https://en.wikipedia.org for image sources and info.

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